Pet litter boxes have long been used for collecting waste from household pets, such as cats and, sometimes dogs that are kept indoors. Such litter boxes generally comprise a container holding a quantity of sand or absorbent particles of a dried clay, such as fuller's earth. Such absorbent materials absorb and hold the urine deposited by the pet and serve to desiccate and partially absorb odor from feces deposited by the using pet.
The conventional litter box has suffered from several disadvantages. First, the particulate litter material used therein has a limited capacity for liquid absorption. Accordingly, it is necessary to empty the soiled litter material and replace it with fresh litter at regular intervals. Additionally, the feces and urine may contain or develop various bacteria and viruses that may infect the pet or be distributed throughout the house by the pet using the litter
Various approaches have been tried to improve the necessary indoor waste disposal. These have included placing a partially enclosed cover over the litter box to control odor and using various deodorizing apparatus within such an enclosed box to reduce odors. In one case it has been proposed to dispense entirely with the litter with the pet depositing its waste upon a solid tray, such as metal, which is then dumped into a container below the tray for drying and evaporation. However, none of these approaches has provided the benefit of the use of particulate litter while providing for extended use of that litter under relatively sanitary conditions.